A battery spacer comprises: a cylindrical case body into which a battery is inserted; a bottom wall portion with which an anode-side end of the battery is to come into contact, the bottom wall portion having an anode exposure hole from which a negative terminal of the battery is partially exposed; an annular top wall member that is located opposite to the bottom wall portion 8 and has a central opening into which the battery is inserted; a plurality of anode-side catching pieces that have anode-side engagement hooks extending from the circumference of the anode exposure hole toward the interior of the case body and engaging with an anode-side outer peripheral surface of the battery, and hold the anode side of the battery; and a plurality of cathode-side catching pieces that have cathode-side engagement hooks extending from the circumference of a central opening toward the interior of the case body and engaging with a cathode-side outer peripheral surface of the battery, and hold the cathode side of the battery.